Sustainability overview

Trout farming was introduced into the UK in the 1950’s, and now there are over 300 trout farms. Rainbow trout is the most popular farmed species of trout, with most of production occurring in a variety of enclosures in freshwater. Farming of trout in ponds and raceways allows for greater control so there are generally fewer impacts to the surrounding environment that in open net pen production. For example the effects of effluent discharge are limited due to sedimentation and treatment practices in place. Trout are carnivorous species that are reliant on fishmeal and fish oil from wild capture fisheries to make their feed. Buying organic farmed trout is the best choice to make as fish stocking densities are generally lower in comparison to non-organic farms, feed is sourced sustainably and welfare of a high standard.

Feed Resources

Criterion Score: -1

Trout feed is traceable to ingredient level however the sustainability of the ingredients cannot be assured. Trout have a significant requirement for fish in their diet, much higher that Atlantic salmon.

Environmental Impacts

Criterion Score: -1

Rainbow trout farming is managed by the countries agencies who control water and chemical use and discharges. Escapes re small scale and have little effect on surrounding wild trout as the farmed fish are infertile. Lethal control of predators is permitted.

Fish Health and Welfare

Management

Criterion Score: 1

There is a regional level planning and a range of regulations to address most of the issues of environmental concern and these are deemed to be broadly effective although specific data is lacking for diseases. The species is farmed to British Quality Trout and organic standards.

Biology

A member of the salmonid family, rainbow trout are native to western North America and range from Alaska to Mexico. They can grow up to 120cm in length and live to an average age of 11 years. They prefer freshwater and require fast flowing water to breed

Farmed seafood criterion scoring overview

This system has been developed by the Marine Conservation Society to help businesses and consumers choose the most environmentally
sustainable fish. For full details, please see the full farmed seafood methodology available
here.

Feed Resources

Score

Descriptor

6

No feed inputs required.

-5 to 5

Feed inputs required. Scored according to traceability, sourcing and ingredients.

-6

Unsustainable, untraceable feed with a high fish feed dependency.

Environmental Impact

Score

Descriptor

7

All environmental impacts are mitigated by technology, production method and/or management practices.

For farmed seafood assessments, a 'critical fail' may be triggered and produce a default red rating where juveniles or broodstock are
sourced from wild capture fisheries that are rated 5, red rated, on the Good Fish Guide. For full details, please see the full farmed
seafood methodology available here.

What’s a sustainability range?

The sustainability of fish can vary significantly depending on how and where it has been caught or farmed. Many single species are caught or farmed in a variety of ways and this range shows that, within a species, some sources may be more sustainable than others.

To find out specific ratings, click on the 'Show options for this fish' button under the image of the fish.

'Best choices' are rated 1 and 2 (green), 'Fish to Avoid' are rated 5 (red). Ratings 3 and 4 mean 'Think' (yellow and amber), as there are better rated alternatives.

Fish that are under review are shown with a question mark icon and no rating.

This system has been developed by the Marine Conservation Society to help consumers and businesses choose the most environmentally sustainable fish.

To be assessed

Seafood sources indicated as, 'To be assessed', are those that have not yet been assessed and assigned a rating or are undergoing a period
of review. These include sources previously rated by MCS for which the rating has lapsed, due to changes in the market or MCS priorities and
resources. Given that these sources are not fully assessed, the profile should not be used to infer the current sustainability of the
fishery or farmed species.

If you are interested in the sustainability of this seafood source, please let us know by emailing
ratings@mcsuk.org

Rating 1

Rating 1 (light green) is associated with the most
sustainably produced seafood.

This system has been developed by the Marine Conservation
Society to help consumers choose the most environmentally
sustainable fish.

Rating 3

Rating 3 (yellow) based on available information; these
species should probably not be considered sustainable at
this time. Areas requiring improvement in the current
production may be significant. Eat only occasionally and
check www.goodfishguide.org for specific details.

This system has been developed by the Marine Conservation
Society to help consumers choose the most environmentally
sustainable fish.

Rating 4

Rating 4 (orange) should not be considered sustainable, and
the fish is likely to have significant environmental issues
associated with its production. While it may be from a
deteriorating fishery, it may be one which has improved from
a 5 rating, and positive steps are being taken. However, MCS
would not usually recommend choosing this fish.

This system has been developed by the Marine Conservation
Society to help consumers choose the most environmentally
sustainable fish.

Red Improver

'Red improver' ratings are assigned to seafood sources which have been assessed and rated 5 (red) due to significant environmental concerns
with one or more aspects of their management, capture or production, yet credible efforts to improve these issues have been agreed through a
Fisheries or Aquaculture Improvement Project – a FIP or an AIP - and work is underway. Such projects are normally publicly listed at
www.fisheryprogress.org. MCS wants to encourage environmental improvements in fisheries and fish farms, and so does not recommend avoiding
these sources, as we normally do for seafood rated 5 (red rated).

'Best choice' fish are rated 1 and 2, Fish to Avoid are rated 5.

This system has been developed by the Marine Conservation Society to help businesses and consumers choose the most environmentally
sustainable fish.

Rating 5

Rating 5 (red) is associated with fish to be avoided on the
basis that all or most of the criteria for sustainablilty
have not been met.